Trivalent influenza vaccine-induced antibody response to circulating influenza a (H3N2) viruses in 2010/11 and 2011/12 seasons

Figures & data

Table 1. Antigenic analysis of influenza A (H3N2) strains in the 2010/11 season

Antigen	HI titer to the antiserum (A/Victoria/210/2009)
A/Victoria/210/2009	1280
A/Osaka/67/2010	640
A/Kobe/357/2010	320
A/Yokohama/79/2010	320

Table 2. HI antibody responses against influenza A (H3N2) strains following vaccination in the 2010/11 season

		Geometric mean titer (95%CI)			Fold increase^a		≥4-fold increase No. (%)		≥1:40 No. (%)
Strain	N	S0	S1	S2^b	S1/S0	S2/S0^b	S1	S2^b	S0	S1	S2^b
A/Victoria/210/2009 (vaccine strain)	54	29 (5–154)	69 (9–500)	83 (11–651)	2.4 (P < 0.001)	2.9 (P < 0.001)	16 (30)	20 (38)	23 (43)	42 (78)	42 (81)
A/Osaka/67/2010	54	12 (3–60)	22 (4–134)	28 (4–175)	1.8 (P < 0.001)	2.2 (P < 0.001)	14 (26)	16 (31)	7 (13)	18 (33)	22 (42)
A/Kobe/357/2010	54	10 (2–46)	21 (4–107)	23 (4–120)	2.0 (P < 0.001)	2.2 (P < 0.001)	14 (26)	17 (33)	5 (9)	17 (31)	19 (37)
A/Yokohama/79/2010	54	10 (2–46)	20 (4–110)	23 (4–125)	1.9 (P < 0.001)	2.2 (P < 0.001)	12 (22)	17 (33)	3 (6)	14 (26)	20 (38)

^aWilcoxon signed-rank test; ^bResults from 52 subjects. CI, confidence interval.

S0, before vaccination; S1, four weeks after the first dose; S2, four weeks after the second dose.

Figure 1. Geometric mean titers (±geometric standard error of the mean) against vaccine strain and circulating strains before vaccination (S0), 4 weeks after the first dose (S1) and 4 weeks after the second dose (S2) in 2010/11 season (A), and before vaccination (S0) and 4 weeks after the dose (S1) in 2011/12 season (B).

Table 3. Antigenic analysis of influenza A (H3N2) strains in the 2011/12 season

Antigen	HI titer to the antiserum (A/Victoria/210/2009)
A/Victoria/210/2009	2560
A/Osaka/110/2011	160
A/Osaka/05/2012	160

Table 4. HI antibody responses against influenza A (H3N2) strains following vaccination in the 2011/12 season

		Geometric mean titer (95%CI)		Fold increase^a		≥1:40 No. (%)
Strain	N	S0	S1	S1/S0	≥4-fold increase No. (%)	S0	S1
A/Victoria/210/2009 (vaccine strain)	31	67 (21–214)	87 (21–368)	1.3 (P < 0.001)	2 (6)	29 (94)	29 (94)
A/Osaka/110/2011	31	17 (3–83)	31 (6–157)	1.8 (P < 0.001)	9 (29)	8 (26)	17 (55)
A/Osaka/05/2012	31	37 (7–195)	50 (9–293)	1.4 (P < 0.001)	8 (26)	21 (68)	26 (84)

^aWilcoxon signed-rank test. CI, confidence interval.

S0, before vaccination; S1, four weeks after the dose.